Bishop Iacob of Daire Coluimb Chille (23 January 1041-), known as Bishop Jacob of Derry in English, was the Bishop of Derry in what is now County Londonderry, Ireland. In 1070, he succeeded Bishop Uargus of Rath Bhoth as Court Chaplain of Ulster under King Einri of Eire. In 1075, he briefly converted to Fraticelli Christianity and sent King Einri excerpts from the Fraticelli writings, attempting to convert him; King Einri instead had Iacob arrested. Einri knew that executing Iacob would lead to a negative reaction from other vassals, so he instead forced him to revert to Catholicism before reinstating him as Court Chaplain. On 10 March 1076, he became the court chaplain of Earl Congalach of Tir Eoghain after Congalach was given control of the Bishopic of Derry, and Ruaidri mac Donnchad succeeded him as Ulster Court Chaplain.